The guardrail post is mainly applied to opposite ends of a guardrail, and used to provide a supporting function. At present, a general guardrail post has a unitary function, and has no other additional functions. If the guardrail post in the central business district is desired to hang a flag or a poster, in conventional practice, a hanging rod is binding to or welded to the guardrail post, and configured to hang the flag or the poster, etc. However, the adopted binding manner causes a certain extent of damage to the guardrail post. If the welding way is adopted, when the flag or the poster is not required to be hung, the hanging rod is left on the guardrail post, affecting the overall impression of guardrail to user.